(99m)Tc-MIBI SPECT Findings in Diabetics with Coronary Artery Disease

BACKGROUND: Evaluation of coronary artery disease(CAD) by radionuclide myocardial perfusion scintigraphy is safe, convenient and informative for diagnosis of CAD & assessment of functional significance of stenotic lesions. We tried to evaluate the characteristics of CAD in dibetics by intravenous dipyridamloe (99m)Tc-MIBI(methoxy isobutyl isonitrile) SPECT(Single Photon Emission Computed Tomography). METHOD: (99m)Tc-MIBI SPECT and coronary arteriography(CAG) were performed simultaneously in less than 2 week interval in 41 diabetics(diabetic group) and 103 non-diabetics(non-diabetic group) with clinical suspicion of CAD. The sensitivity and specificity of (99m)Tc-MIBI SPECT for detection of CAD were compared between two groups. The site and number of involved vessels, the extent of perfusion defect and redistribution pattern were compared between two groups. RESULT: 1) The sensitivity and specificity of (99m)Tc-MIBI SPECT for detection of CAD were 97% and 80% in diabetics, these were comparable to those in non-diabetics(97% and 78%). 2) Three vessel disease were common(p<0.01)in diabetics(SPECT 28.1%, CAG 32.3%) than in non-diabetics(SPECT 11.4%, CAG 7.5%). Distal lesions were also more common(p<0.005) in diabetics(CAG 40.3%) than in non-diabetics(CAG 15.7%). 3) On stress SPECT, the extent of perfusion defect was not different in individual vessel areas between diabetics and non-diabetics. However the perfusion defect of left ventricle as a whole was significantly higher(p<0.05) in diabetics(35.2+/-16.2%) than in non-diabetics(26.4+/-15.5%). 4) On rest SPECT, the percent redistribution was significantly lower in diabetics than in non-diabetics(left anterior descending artery area ; diabetic group 31.1+/-22.5% vs non-diabetic group ; 49+/-28.5%, p<0.05, left ventricle as a whole ; diabetic group 30.6+/-21.2% vs non-diabetic group 48.2+/-27.6%, p<0.02). CONCLUSION: Quantitative (99m)Tc-MIBI SPECT provided high sensitivity and specificity for detection of CAD in diabetics. Multiple vessel disease, distal lesion and fixed lesions were more common in diabetics than in non-diabetics, (99m)Tc-MIBI SPECT is useful noninvasive test for diagnosis of CAD & important prognostic implications.

The Novel Low Frequency Oscillation in Pulmonary Artery Pressure

BACKGROUND: It is well known that systemic blood pressure oscillates with low(0.04~0.1Hz), mid(0.1~0.15Hz), and high(respiratory) frequency range. But there has been no study about oscillation of pulmonary artery pressure(PAP). METHOD: We measured PAP for 5 minutes in 32 patients of ventricular septal defect and stored them to computer files. Power spectral density curve was obtained. Low, mid, respiratory frequency power were measured by integrating the area within each frequency range below the power density curve. RESULT: The incidence of significant low frequency power(more than 5% of total power) were higher in patients of high PAP and hign Rp/Rs than those of low PAP and Rp/Rs(p<0.01 and p<0.005 respectively). The low frequency power positively correlates with PAP and Rp/Rs(r=0.62, p<0.0005 and r=0.61, p=0.0005 respectively). CONCLUSION: It can be said conclusively that as PAP and pulmonary vascular resistance elevates, the PAP tends to definitively oscillate in low frequency range.